Rotary valve internal combustion engines possess several significant advantages over conventional poppet valve internal combustion engines, including significantly higher compression ratios and revolutions per minute (RPM), meaning more power, a much more compact and light-weight cylinder head, and reduced complexity, thus potentially leading to higher engine reliability and lower maintenance and/or repair costs.
Rotary valves are potentially highly suitable for high-revving internal combustion engines, for example, such as those used in racing sports cars and Formula One (F1) racing cars, on which traditional poppet valves with springs can fail due to valve float and spring resonance and where the desmodromic valve gear is too heavy, large in size and too complex to time and design properly. As previously noted, rotary valves could allow for a more compact and lightweight cylinder head design, which is an important design consideration for sports cars and racing cars. These types of valves typically rotate at half engine speed and lack the inertia forces of reciprocating valve mechanisms. This allows for higher engine speeds and potentially offers significantly more power than conventional poppet valve internal combustion engines.
Conventional rotary valve internal combustion engines typically employ a cylinder head that includes a rotary valve mechanism that allows an incoming air/fuel charge into the particular cylinder of the engine and any resulting combustion gases out of the cylinder through an exhaust rotary valve mechanism into an exhaust manifold or header. These conventional rotary valve internal combustion engines typically include a seal, for example, of various shapes and sizes, that seals against a rotary valve rotor to prevent combustion gases and pressure from escaping out of the combustion chamber. The seal also presumably prevents any leakage of any incoming air and fuel coming into the combustion chamber from the intake manifold, as well as any outgoing exhaust gases exiting from the combustion chamber. The rotary valve seal is stationary and the rotary valve face is constantly rubbing against this seal (e.g., during each successive rotation), wearing both the rotor surface and seal face where these parts are in constant contact with one another. This “static” type of seal is sometimes pressed into the cylinder head itself and the rotary valve rotor rests directly on top of the seal to contain the combustion gases and pressures, and to seal off any path into and out of the combustion chamber for both the intake and exhaust manifolds.
Some of the problems associated with these types of seal designs are the constant wearing and friction that exists between these parts, the mechanical losses because of the friction that exists there, and, because of this constant contact, the rotor seal wearing out and eventually allowing the combustion gases to leak out and prevent complete combustion within the cylinder. Rotary valve engine designers have tried numerous different rotor seal design iterations, and materials used therefor, only to have the same constant contact wear and leakage issues to deal with (sometimes very quickly) because of this static type of seal design.
Accordingly, there exists a need for new and improved rotary valve internal combustion engine systems that overcome at least one of the aforementioned deficiencies.